USB Attached SCSI Protocol is a more efficient technology for the transfer of data over a USB connection. Although USB 3.0 is much faster than USB 2.0, its full performance cannot be unleashed without also upgrading the existing data transfer protocol, known as Bulk-Only Transport (BOT).
Most USB 3.0 devices will operate using BOT unless specific drivers are installed and UAS compatible hardware is used at each end of the connection. Some vendors, such as Asus, have released UASP drivers for Windows 7; full native OS support was introduced with Windows 8.